<template>
   <div class="home-page">

  <div class="banner">
    <div class="container">
      <h1 class="logo-font">conduit</h1>
      <p>A place to share your knowledge.</p>
    </div>
  </div>

  <div class="container page">
    <div class="row">

      <div class="col-md-9">
        <div class="feed-toggle">
          <ul class="nav nav-pills outline-active">
            <li class="nav-item" v-if="user">
              <nuxt-link class="nav-link" exact :to="{name:'home',query:{tab:'feed'}}" :class="{active:tab==='feed'}">Your Feed</nuxt-link>
            </li>
            <li class="nav-item">
              <nuxt-link class="nav-link" exact :to="{name:'home'}" :class="{active:tab==='global'}">Global Feed</nuxt-link>
            </li>
            <li class="nav-item" v-if="tag">
              <nuxt-link class="nav-link" exact :to="{name:'home',query:{tab:'tag',tag:tag}}" :class="{active:tab==='tag'}">{{tag}}</nuxt-link>
            </li>
          </ul>
        </div>

        <div class="article-preview" v-for="article in articles" :key="article.slug">
          <div class="article-meta">
            <nuxt-link :to="{name:'profile',params:{'username':article.author.username}}">
              <img :src="article.author.image" />
            </nuxt-link>
            <div class="info">
              <nuxt-link :to="{name:'profile',params:{'username':article.author.username}}">
                {{article.author.username}}
              </nuxt-link>
              <span class="date">{{article.createdAt | date('MMM DD, YYYY')}}</span>
            </div>
            <button class="btn btn-outline-primary btn-sm pull-xs-right" :class="{active:article.favorited}"
            @click="onFavorite(article)" :disabled="article.favoritedDisabled">
              <i class="ion-heart"></i> {{article.favoritesCount}}
            </button>
          </div>
          <nuxt-link :to="{name:'article',params:{slug:article.slug}}" class="preview-link">
            <h1>{{article.title}}</h1>
            <p>{{article.description}}</p>
            <span>Read more...</span>
          </nuxt-link>
        </div>
        
        <nav>
          <ul class="pagination">
            <li class="page-item " v-for="item in totalPage" :key="item">
              <nuxt-link class="page-link ng-binding" :to="{
                name:'home',
                query:{page:item,tag:$route.query.tag,tab:tab}
                }">{{item}}</nuxt-link>
            </li>
          </ul>
        </nav>
      </div>

      <div class="col-md-3">
        <div class="sidebar">
          <p>Popular Tags</p>
          <div class="tag-list">
            <template  v-for="tag in tags" >
              <nuxt-link :key="tag" class="tag-pill tag-default" :to="{name:'home',query:{tab:'tag',tag:tag}}">{{tag}}</nuxt-link>
            </template>
          </div>
        </div>
      </div>

    </div>
  </div>
</div>
</template>
<script>

import {getArticles,getFeedArticles,addFavorite,deleteFavorite } from '@/api/article'
import {getTags} from '@/api/tag'
import {mapState} from 'vuex'
export default {
    name:'homeindex',
    watchQuery:['page','tag','tab'],
    computed:{
      totalPage(){
        return  Math.ceil(this.articlesCount / this.limit)
      },
      ...mapState(['user'])
    },
    async asyncData({query}){
      let limit = 20
      let page = Number.parseInt(query.page || 1)
      let tab = query.tab || 'global'
      let tag = query.tag
      const [articelRes,tagRes] = await Promise.all([
        tab === 'feed' ?
            getFeedArticles({limit: limit, offset : page * (limit - 1)})
          : getArticles({limit: limit, offset : page * (limit - 1), tag:query.tag}),
        getTags()
      ])
      const articles = articelRes.data.articles.map(item=>{
        item.favoritedDisabled = false
        return item
      })
      return {
        articles: articles,
        articlesCount: articelRes.data.articlesCount,
        limit,
        tags: tagRes.data.tags,
        page,
        tab,
        tag
      }
    },
    methods:{
     async onFavorite(article){
        article.favoritedDisabled = true
        if(article.favorited){
          await deleteFavorite(article.slug)
          article.favorited = false
          article.favoritesCount --
        }else{
          await addFavorite(article.slug)
          article.favorited = true
          article.favoritesCount ++
        }
        article.favoritedDisabled = false
      }
    }
}
</script>